COUPLING DEVICE AT A TRACTOR

Abstract: A coupling device at a tractor is described, provided with a three-points fastening for tools, with an upper top beam, with a 1:st substantially horizontally displaceable fastening link, and two lower traction beams, with 2:nd and 3:rd substantially vertically displaceable fastening links, and a power output in the form of a substantially horizontally rotating shaft, directed in the longitudinal direction of the tractor. It comprises a first coupling frame, fastened hinged (6, 7, 8) at said 1:st to 3:rd fastening links, and a second coupling frame, provided with at least an upper (25) and two lower (26, 27) fastening links for hinged fastening of a tool, the first coupling frame being provided with a first coupling element (16) in longitudinal- and direction variable rotation connection with said rotating shaft of the tractor, the second coupling frame being provided with a second coupling element (28) being able to be connected to rotation connection with the first coupling element, to transfer the effect of said rotating shaft to the tool, the coupling frames being provided with cooperating upper and lower fastening elements. The coupling device is primarily characterized in that the upper fastening element of the first coupling frame consists of two fastening hooks (9, 10), turned from the tractor, provided at a distance from each other symmetrically from the vertical symmetric axis of the coupling frame, converging upwards towards each other, and that the second coupling frame comprises an upper beam element (20) in each end limited by downwardly directed limiting elements (21, 22). The fastening hooks and the beam element are formed and provided in such a way, that the fastening hooks can be brought, from below, to vertically and horizontally correct coupling with the horizontal beam element, also when the first and second coupling frames are somewhat mutually twisted in a plane perpendicular to the longitudinal direction of the tractor.

Description: Coupling device at a tractor The present invention relates to a coupling device at a tractor, provided with a three- points fastening for tools, with an upper top beam, with a l:st substantially horizontally displaceable fastening link, and two lower traction beams, with 2:nd and 3:rd substantially vertically displaceable fastening links, and a power output in the form of a substantially horizontally rotating shaft, directed in the longitudinal direction of the tractor, comprising,a first coupling frame, fastened hinged at said l:st to 3:rd fastening links, and a second coupling frame, provided with at least an upper (25) and two lower fastening links for hinged fastening of a tool, the first coupling frame being provided with a first coupling element in longitudinal- and directionvariable rotation connection with said rotating shaft of the tractor, the second coupling frame being provided with a second coupling element being able to be connected to rotation connection with the first coupling element, to transfer the effect of said rotating shaft to the tool, the coupling frames being provided with cooperating upper and lower fastening elements. Several coupling devices for tractors are known. A compilation of such, utilized or just suggested is given in the Swedish Patent Application SE- 8104211-1, published as laid open publication No. 434000 on 1984 July 2nd.In this publication coupling devices of all conceivable types are described, also of the art mentioned introductorily. There is also a list of the demands for such coupling devices. Among those demands may be mentioned: - possibility to couple the tools quickly and easily, - possibility to adjust the coupling easily and simply. Among the described couplings some are very complicated and expensive, and furthermore they do not meet said two demands. Thus the object of the invention is to provide a coupling device of the type mentioned introductorily, which is simple and relatively inexpensive in construction and manufacture, and which admits simple and safe coupling of tools to the tractor, and that can be easily adjusted according to needs. According the invention such a coupling device is characterized primarily in that the upper fastening element of the first cuopling frame consists of two fastening hooks ,turned from the tractor, provided at a distance from each other symmetrically from the vertical symmetric axis of the coupling frame, converging upwards towards each other, and that the second coupling frame comprises an upper beam element, in each end limited by downwardly directed limiting elements, the fastening hooks and the beam element being formed and provided in such a way, that the fastening hooks can be brought, from below, to vertically and horizontally correct coupling with the horizontal coupling frame, also when the first and second coupling frames are somewhat mutually twisted in a plane perpendicular to the longitudinal direction of the tractor. Advantageously the fastening hooks are formed with their limiting surfaces turned to the tractor, seen from above tilting towards the tractor. In one suitable embodiment of the invention, the first coupling frame is formed substantially rectangular, which is advantageously also the case with the second coupling frame. Said beam element is, in one preferred embodiment, formed with a circular cylindrical outer limiting surface. The limiting element of the beam element suitable forms walls in the second coupling frame. The fastening hooks may be formed in different ways, under the provision, that they admit said desired function, in one advantageous embodiment the outer limiting surfaces of the fastening hooks, seen laterally, are convex, preferably generated by radii in a vertical plane substantially equal to the distance between said limiting elements. Of course a certain play is needed, in order that the fastening hooks and the beam element resp their limiting surfaces shall not get in binding connection. In one further suitable embodiment of the coupling device according to the invention, the lower cooperating fastening elements of the coupling frames comprise guide elements, provided at the first coupling frame to guide correctly the fastening elements of the second coupling frame to engagement with the fastening elements of the first coupling frame. In one further embodiment, that may be suitable in some cases, the lower fastening links of the second coupling frame are formed by bushings provided in the lower part of the limiting elements, thorugh which a shaft at the tool is attached to form a subatntially rectangular unit. The invention shall be described more in detail in the following, reference being made to the enclosed figures, of which: figures 1 a- c schematically show an embodiment of the first coupling frame according to the invention, in a view towards the tractor, a view from the side resp a view from the tractor, figure 2 a schematically shows the coupling frame in figure 1, in perspective towards the tractor, figure 2 b schematically shows a detail in figure 2 a in an alternative form, figure 3 schematically shows the coupling frame in figure 1, in perspective from the tractor, figure 4 a- c schematically show an embodiment of a second coupling frame according to the invention, figure 4 a showing a perspective view from the tractor, 4 b a view from the side and 4 c shows a perspective view towards the tractor, figure 5 schematically shows a special embodiment of a first and a second coupling element, figure 6 schematically shows an adaption element for the second coupling device, figures 7 a-b schematically show an embodiment of the second coupling frame with a detail of the lower fastening link, figure 8 schematically shows a three-part cardan shaft for the transmission of rotation movement. As is obvious from figures 1 a- c, 2 a and 3 a rectangular first coupling frame is formed by an upper beam 1, two side beams 2 and 3 and a lower beam 4. A supporting plate 5 is inserted between the side beams and the lower beam. In the upper beam a fastening device 6 i sporvided for hinged connection with the fastening hinge on the upper top beam of the tractor, which is horizontally displaceable via a hydraulic device. From the side beams two link taps 7 and 8 protrude, intended to be connected, hinged, to the fastening hinges of the traction beams of the tractor. The traction beams are vertically displaceable by corresponding hydraulic devices. At the upper portion of the coupling frame, that is to say in the corners formed by the upper beam 1 and resp side beams 2 and 3, two fasteing hooks are attached, converging towards each other upwardly. They are also so formed, that their limiting surfaces towards the tractor show an inclination seen from above and towards the tractor. In the lower portion of the coupling frame, at the corners formed by the lower beam 4 and the side beams 2 an3 there are provided guides 11 and 12, at the side turned from the tractor, which lead into holes made in the support plate 5. At the other side of the support plate there is a hydraulic device 13 with two pistons 14,15 attached to the lower beam 4. At the support plate a first coupling element 16 is provided, comprising a shaft tap 17, intended to be connected to a not shown rotation connection, longitudinally and directionally variable, to the power output of the tractor, in the form of a rotating shaft. The coupling element is provided, at the side turned from the tractor, with a first coupling means 18 with three pins 19, springloaded from within. In figure 2b an alternative embodiment of the first coupling means is shown marked 18 A. In figure 4 a to c a second coupling frame is shown, intended to be attached to the tool. It also shows a rectangular form and is formed by an upper horizontal beam element 20, which shows a circular cylindrtical outer surface, at the sides connected to two side beams 21 and 22, which in turn carry a lower beam 23. A support plate 24 is insertred between the lower beam 23 and the side beams 21 and 22. An upper fastening device 25 is mounted at the middle of the beam element 20 and lower fastening devices 26 and 27 are fastened to the lower portions of side beams 21 and 22. The fastening devices 25,26 and 27 are intended to be fastened, hinged at corresponding means at the tool.The support plate 24 carries a second coupling element 28, comprising a shaft tap 29 intended to transfer, after coupling of the first and the second coupling element, of the rotating effect of the tractor to the tool.The second coupling element is, at its side turned from the shaft tap 29, provided with a second coupling means 30, intended to cooperate with the coupling means at the first coupling frame to transfer the rotation movement. The coupling means can be provided with cooperatring guide means to be connected safely also in cases of a certain excentricity, as has been indicated in figure 2 b. The second coupling frame is, at the lower portions of the side beams, provided with fastening cantilevers 31 and 32, intended to be guided by said guides 11 and 12 at the first coupling frame, when the first and second ccoupling frames are connected, to such a position in relationship, to said pistons 14 and 15, that these, when said hydraulic device is activated, will lock the the first coupling frameat the second one at the lower portion. In figure 5 a special, advantageous embodiment of the first and second coupling elements is shown. One of these, marked 33, has a central hole 36 and four more circumferentially arranged holes 38, whilst the second coupling element marked 34 is provided with a central, guiding cone 35 and four taps 37, corresponding to the holes 38. In order to adapt the seconsdd coupling frame with its side beams 21,22 to its tool, an adaption element 39, shown in figure 6 can be used. The adaption element 39 is formed, as is seen, as a double folded iron piece with holes 41 for fastening into the corresponding holes 40 of the side beam 21 by aid of bolts or the like. The holes 42 shown are intended for fastening at the tool used. This adaption element can, is is obvious, be turned inwardly or outwardly, which admits adaption to tools showing different widths. The coupling device according to the invention thus operates in such a way, that the first coupling device is attached to the three fastening points of a tractor, whereupon a device with at least two cardan links is is provided to connect, longitudinally and directionally variable, the power output of the tractor in the form af a rotating shaft, to the shaft tap 17 at the first coupling tap. The second coupling frame is mounted in a corresponding way, to the tool, that is under view. Of course it is advantageous to have a set of second coupling frames available fo the number of tools, that is intended to be used at a certain period of the cultivation year. The tractor is reversed towards the tool, so that the fastening hooks 9 and 10 are moved in under the beam element 20 to lift this. Also if the first and second coupling frames would be somewhat twisted in a plane perpendicular to the longitudinal direction of the tractor the beam element and the fastening hooks will be brought into the correct mutual position vertically and horizontally due to the form of the fastening hooks. In figures 7 a and 7 b an alternative embodiment is shown of the second coupling frame, where the lower fastening hinges 43,44 form bushings in the lower portions of the limiting elements 45,46, through which a shaft at the tool is attached by collets 48 and cotters 49.This fastening is made possible in that the upper horizontal beam element of the coupling frame in this case is formed longitudinally variable and consists of two beam portions 51 and 52, which are internally threaded with opposite pitch, in order that the turning of a shaft 53, threaded externally in the corresponding way, varies the length of the upper beam element. In figure 8 there is shown a three-part cardan shaft 50 for the flexible transfer of a rotation movement between a first coupling element 16 and a second coupling element 28.

Claims: Patent claims 1. A coupling device at a tractor, provided with a three- points fastening for tools, with an upper top beam, with a list substantially horizontally displaceable fastening link, and two lower traction beams, with 2:nd and 3:rd substantially vertically displaceable fastening links, and a power output in the form of a substantially horizontally rotating shaft, directed in the longitudinal direction of the tractor, comprising, a first coupling frame, fastened hinged at said l:st to 3:rd fastening links, and a second coupling frame, provided with at least an upper (25) and two lower (26,27) fastening links for hinged fastening of a tool, the first coupling frame being provided with a first coupling element (16) in longitudinal- and directionvariable rotation connection with said rotating shaft of the tractor, the second coupling frame being provided with a second coupling element (28) being able to be connected to rotation connection with the first coupling element, to transfer the effect of said rotating shaft to the tool, the coupling frames being provided with cooperating upper and lower fastening elements, characterized in that the upper fastening element of the first cuopling frame consists of two fastening hooks (9,10), turned from the tractor, provided at a distance from each other symmetrically from the vertical symmetric axis of the coupling frame, converging upwards towards each other, and that the second coupling frame comprises an upper beam element (20) in each end limited by downwardly directed limiting elements (21,22), the fastening hooks and the beam element being formed and provided in such a way, that the fastening hooks can be brought, from below, to vertically and horizontally correct coupling with the horizontal beam element , also when the first and second coupling frames are somewhat mutually twisted in a plane perpendicular to the longitudinal direction of the tractor. 2. A coupling device according to claim 1, characterized in that the fastening hooks (9,10) are formed, with their limiting surfaces, turned to the tractor, tilting towards the tractor, seen from above. 3. A coupling device according to claim 1 or 2, characterized in that the coupling frames are formed substantially rectangular. 4. A coupling device according to any of claims 1 to 3, characterized in that said beam element (20) has a circular cylindrical outer limiting surface. 5. A coupling device according to any of claims 1 to 4, characterized in that said limiting elements form sides (21,22) in the second coupling frame. 6. A coupling device according to any of claims 1 to 5, characterized in that the limiting surfaces of the fastening hooks (9,10) seen laterally, are convex, preferably generated in a vertical plane by radii, substantially equal to the distance between said limiting elements. 7. A coupling device according to any of claims 1 to 6, characterized in that the lower, cooperating fastening elements of the coupling frames comprise guide elements (11,12) provided at the first coupling frame to guide correctly the fastening elements of the second coupling frame to engagement with the fastening elements of the first coupling frame. 8. a coupling device according to any of claims 1 to 7, characterized in that the lower fastening links (43,44) of the second coupling frame are formed by bushings provided in the lower part of the limiting elements (45,46) , thorugh which a shaft (47) at the tool is attached. 9. A coupling device according to any of claims 1 to 8, characterized in that the first coupling element (16) is connected to the second coupling element (28) by a three-part cardan shaft (50).

Inventors: ENGLUND LARS, ENGLUND, LARS
Applicants: ENGLUND LARS, ENGLUND, LARS
Application year: 1994
Main classification: A01B59
IPC codes: A01B59, A01B71